1. Field of the Invention
This invention relates to methods and kits for detecting the presence of chemical warfare agents and degradation products thereof More particularly, the invention relates to an accurate and rapid method of detecting the presence of chemical warfare agents, precursors of chemical warfare agents, and degradation products of chemical warfare agents in a sample.
2. Description of the Prior Art
Over the years, various highly toxic chemical warfare agents (CWA's) have been developed and stockpiled by several nations. In view of the biological hazards associated with CWA's and degradation products thereof, chemical warfare conventions (CWC's) have been developed by certain countries. These CWC's monitor, identify and, if necessary, dispose of CWA's which are not in compliance with the convention. As a result of the convention, it is often necessary to conduct inspections of various sites in order to assure compliance.
On-site analysis of sample unknowns in CWC verification inspections is preferred to off-site analysis. Some reasons for this preference include:
a) existing agreements call for on-site analysis; PA1 b) when samples are analyzed on-site, ambiguities can be resolved during the inspection; PA1 c) since unknown samples are not removed from the inspection site, contamination and cross-contamination of samples during travel to off-site laboratories cannot occur; and PA1 d) since ambiguities will be resolved on-site during the inspection, the inspection report that is completed at the end of the inspection would not be subject to challenge. PA1 contacting a sample suspected of containing a member of the group consisting of chemical warfare agents, chemical warfare agent precursors, chemical warfare agent degradation products and mixtures thereof with a sufficient amount of a chromatographic adsorbent material and a sufficient amount of a chromogenic detector reagent, so that a chromogenic indicator is formed when the sample contains a member of the aforementioned group of chemical warfare agents. PA1 a) means for obtaining a sample suspected of containing a member of the group consisting of chemical warfare agents, chemical warfare agent degradation products and mixtures thereof, PA1 b) a sufficient amount of a chromatographic adsorbent material PA1 c) a sufficient amount of a chromogenic detector reagent, PA1 d) means for reacting the sample, chromatographic adsorbent material and chromogenic detector reagent PA1 so that a chromogenic indicator can be formed when the sample contains of the aforementioned member of the group. PA1 contacting a sample suspected of containing a member of the group consisting of chemical warfare agents, chemical warfare agent precursors, chemical warfare agent degradation products and mixtures thereof with a sufficient amount of a chromatographic adsorbent material and a sufficient amount of a chromogenic detector reagent PA1 whereby a chromogenic indicator is formed when a sample contains a member or analyte of the group.
One of the requirements for the screening methods employed in on-site inspections is that they be essentially non-intrusive. Every possible effort must be made to utilize analytical methods that do not allow the loss of sensitive corporate or governmental information during on-site inspections. Reagent-based screening methods are attractive because many tests can be run in a short period of time and, since they give only a positive or negative response, they are capable of providing presumptive evidence for a prohibited substance in a sample without revealing the identity of any of the components in the sample.
Consequently, a number of reagent based screening tests have been included in the initial operating capability (IOC) for the on-site CWC verification inspections. Unfortunately, these tests do not have a high degree of detection specificity.
Classical spot tests are usually carried out in a porcelain spot plate containing depressions to which detector reagents are added. In practice, a small amount of a test sample, hereinafter, "a sample unknown" is placed in one or more of the depressions of the spot plate. Small quantities of one or more reagents are then added to it. A positive test is usually signified by a color change. As many as 12 different spot tests can be carried out in a small (3.5.times.4.5 inch) spot plate. In most cases, the lower limit of detection is in the 1-100 microgram range. More sensitive testing methods for on-site inspections would be welcomed.
In view of the advantages of rapidly and accurately identifying the presence of CWA's and associated by-products, and further in view of the need to address the shortcomings associated with currently available detection methods, there is still a need for new and improved detection methods and kits. In particular, there remains a need for rapidly and accurately detecting submicrogram quantities of CWA, CWA precursors and related degradation byproducts. The present invention addresses these needs.